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Hard winter for Gulf manatees, dolphins

Manatees enjoy the warm spring waters Jan. 28, 2010, in Crystal River, Fla. The cold winter weather drives the marine mammals into the 72-degree spring water and are popular with tourists from all over the world.

The Associated Press/File

JANET McCONNAUGHEYThe Associated Press

Published: Wednesday, March 2, 2011 at 6:47 p.m.

Last Modified: Wednesday, March 2, 2011 at 6:47 p.m.

NEW ORLEANS — Cold weather has taken a toll for the second year in a row on one of the Gulf Coast's most interesting creatures — the gentle, half-ton manatees that winter in Florida waters and that some believe have inspired legends about mermaids.

Manatees have died in near-record numbers since New Year's Day, according to Florida Fish and Wildlife Conservation Commission data.

They aren't the only Gulf Coast creatures whose deaths have been notable of late. Baby and adult bottlenose dolphins also have been dying in large numbers from an unknown cause. But scientists say the spike in manatee deaths is clearly related to cold; the dolphin deaths are still under investigation.

Babies accounted for only seven of the 161 manatees that have died from Jan. 1 through Feb. 25, according to figures posted Wednesday on the commission's website. That's not an unusually high number. But, with a few days left in February, it was already the second-highest manatee death toll on record for the first two months of the year.

"Anywhere in Florida, we haven't seen the problems in small calves like they've seen in dolphins," said Martine DeWitt, a veterinarian at the commission's Fish and Wildlife Research Institute.

Florida manatees, a subspecies of the West Indian manatee, live year-round in the peninsula's coastal shallows and inlets. In warmer months, some travel up the East Coast as far as Virginia and west into Texas waters. One was tracked as far north as Rhode Island. But they can't handle chills and return to Florida before winter.

"Manatees really need temperatures higher than 68 degrees Fahrenheit, while dolphins are OK in water colder than that," Dewitt said. "Manatees have less insulation than dolphins. Even though they look big and fat, they do not have blubber to protect them, as dolphins have."

The record death toll for January and February — also from cold — was last year, when 364 manatees died in the first two months. The total for the year in Florida waters was 767.

Cold caused at least 279 of the 2010 deaths, including the deaths of 21 of 96 newborns. So far this year, at least 91 have died of cold, compared to 185 by last Feb. 25.

Cause of death couldn't be determined for 40 as of Feb. 25.

But Carli Segelson, spokeswoman for the Fish and Wildlife Research Institute, said cold weather is likely the cause for many of them.

Other deaths as of Feb. 18 included 11 from collisions with watercraft.

The federal government is tracking animal deaths in the area hit by last year's BP oil spill as part of its investigation of the spill's effects.

By Tuesday night, 83 dead dolphins had been found from the start of the Florida Panhandle to the Texas state line, 44 of them calves. Although the last year's vast oil spill is being investigated as a possible cause, so are disease, naturally occurring biotoxins and the cold winter. Scientists say it will be months before they get results from lab tests for all of those.

Just as the U.S. Geological Service keeps track of mass deaths of birds, reptiles and other animals — like the bird deaths earlier this year in states including Arkansas, Louisiana, Pennsylvania, Tennessee and Kentucky — NOAA does for marine mammals.

They're harder to keep tabs on than animals that live on or fall to earth. But, nationwide, NOAA has logged 51 "unusual mortality events" of marine mammals since 1991, including last year's manatee deaths.

If experts conclude that the oil spill played a part in the dolphin deaths, it would be only the fourth listing for "human interaction."

The others include blue whales killed by collisions with ships in the Santa Barbara Channel off Southern California in 2007 and shootings that killed at least 50 of more than 1,000 sea lions and seals in Washington State in 1993. In 1996, blast injury was suspected but not proved to cause deaths of right whales in Florida and Georgia waters.

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